What brand is it? I am no expert. What I know is goods manufactured in the US and Canada are free of a customs duty because of NAFTA and should be no problem. They may ask for a disclosure form. If a foreign make, they may want a duty charge. If the unit is something not sold in the US at all, I don't know what could happen.
In any event expect to pay a processing fee even if no customs duty due. I don't believe they can keep it without just cause (it would be theft). I have a friend who works with dogs that look for drugs and food not shipped properly. I will ask them.